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Aug. 30, 1932. P. WRIGHT EXHAUST snmiqna Filed Sept. 6, 1929 FIG.

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Patented Aug. 30, 1932 UNITED STATES.

PATENT OFFICE THEODORE P. WRIGHT,-OF PORT WASHINGTON, NEW YORK, ASSIGNOR TO CURTISS AEROILANE & MOTOR COMPANY, INC A CORPORATION OF NEW YORK EXHAUST SILENOER Application filed September 6, 1929. Serial No. 890,667.

My invention relates to aircraft and more partlcularly to methods of and apparatus for minimizing or deadening the sounds of the exhaust of motors used in aircraft.

5 It is well known that the ordinary automobile engine muffler appreciably reduces the elficiency of the motor. Furthermore, the mufilers which have been developed for automobiles are comparatively heavy and, when used with aircraft, occasion considerable wind resistance. They are, for these and other reasons, not well suited for aeronautical uses. On the other hand, when the motor exhaust is allowed to be discharged without any attempt to minimize the sound, the noise thereof becomes very disagreeable to passengers.

One of the objects of my invention is to provide methods of and means for reflecting the sounds and fumes of the exhaust of aeronautical motors away from the occupants of the aerial vehicle.

Afurther object is the provision of suitable means for minimizing the sounds of the exhaust, which means will be comparatively light in weight and will occasion comparatively little additional drag.

A further object of my invention is to locate the exit of exhaust gases of aircraft 3o motors at such a point with reference to the occupants of the aerial vehicle that the fumes, sound and vibration occasioned by the exhaust will produce the least objectionable effect upon the occupants. 1

Further objects will be apparent from reading of the subjoined specification and claims and from a consideration of the'draw- 1n n order to explain the invention more clearly, an embodiment thereof is shown in the accompanying drawing, in which:

Fig.1 is a view in sideelevation of an airplane equipped with one form of apparatus constructed according to my invention;

Fig. 2 is a view of a detail of the apparatus of Fig. 1 shown on a somewhat larger scale than it is shown in.Fig. 1, but with parts broken away and with the sound reflector shown in section; and I Fig. 3 is a view in rear elevation of a part of an airplane equipped with a different embodiment of my invention, with the exhaust pipe and sound reflector shown in section.

The apparatus shown in Figs. 1' and 2 for illustration of my invention comprises an airplane equipped with a motor and having an exhaust manifold leading from the motor and an exhaust conduit leading from the manifold. .One end of the exhaust conduit is open to the atmosphere and is positioned under a wing of the airplane. Adjacent to and extending over the open end of the exhaust conduit, there is shown one form of an improved sound reflector. The sound reflector is constructed of suitable metal, has an open front end and an open bottom, and toward its rear end is curved so that the exhaust gases coming out of the exhaust pipe and the sound waves accompanying them are gradually reflected downward and away from the airplane.

Referring particularly to the preferred embodiment of my invention illustrated in Figs. 1 and 2 of the drawing, there is illustrated an airplane indicated generally by the numeral 11. The airplane lllhas a fuselage 12 and wings one of which is designated 13. Housed within the nose 14 of the fuselage 12 is a motor from which exhaust pipes 16 lead to an exhaust manifold 17 Connected to the rear end of this exhaust mani- 23 gradually curved downward and thus insures that the exhaust gases and sound waves issuing from the conduit 19 shall be reflected downward.

The sound reflector 21 is fastened to the underside of the wing 13 of the airplane. Secured to the sides of said reflector 21 are flanges 24 25, 26 and 27; and bolts 28, 29, 31 and .32 are fastened to the wing 13 and to the flanges 24., 25, 26 and 27 respectively.

' of the aircraft.

The operation of this form of my invention will be apparent from the above descrip-s tion. The exhaust gases and motor sounds released from the exhaust pipes 16 pass through the manifold 17 and the conduits 18 and 19 to a point beneath the sound reflector 21 and by the action of the sound reflector 21 and especially by reason of the shape of the rear portion thereof, are reflected downward into the open air away from the fuselage of the airplane and away from the occupants thereof. Inasmuch as the sound reflector is located beneath the wing, the air flow caused by the wing itself aids in this reflection and the dead air space within the wing serves further to deaden the sound to the occupants It is to be noted that the sound reflector 21.is spaced from'the wing and that this space also aids in deadening the sound of theexhaust. The shape of the sound reflector not only serves efliciently to reflect the sound from the airplane, but also provides that the reflector shall produce a minimum of drag and shall at the same time produce a certain amount of lift. As may be readily understood, the reflection of the obnoxious exhaust gases away from the occupants is also highly desirable.

IVhile I have only illustrated one exhaust manifold, it is to be understood that I may use more than one. For instance, I may provide an exhaust manifold on each side of the 'motor, which will by suitable conduits, conduct the exhaust gases and sounds to deflectors located, if desired, beneath both wings.

In Fig. 3 I have illustrated a slightly different arrangement. Instead of allowing the exhaust gases to be discharged beneath one of the wings 13 or 13 I have provided an arrangement by which the discharge may take place beneath the fuselage 12. As there shown, exhaust conduits 18 and 18 lead from the exhaust manifolds on both sides of the motor in a somewhat similar manner to that in which the exhaust conduit 18 leads from the exhaust manifold 17. The conduits 18 and 18 converge into a common horizontal conduit l9 which has its open end positionedwithin a sound reflector 21. The sound reflector 21 is similar in all respects to the reflector 21 and is secured to the bottom of the fuselage 12' by means of a plurality of flanges such as those shown at 24 and 25 and a plurality of bolts such as those shown at 28 and 29*.

In the operation of this form of my invention the exhaust gases and the sound of the exhaust are reflected away from the occupants of the airplane in substantially the same manner as that explained above in'connection with the embodiment of my invention shown in Figs. 1 and 2.

It is to be understood that the above described embodiments of my invention are for the purpose of illustration only and various changes may be made therein without departing from the spirit and scope of my invention.

I claim as my invention:

1. In an aerial vehicle having a fuselage, supporting wings, a motor and an exhaust conduit for conveying exhaust gases and sound waves away fromthe motor, a sound reflector adjacent to and overlying the outlet end of said exhaust conduit, said sound deflector being formed substantially as one half of a hollow cylinder with its forward end open and "with the upper surface curving gradually downward and backward and said deflector being positioned with its open side facing downward and away from said fuseage.

2. A sound and exhaust reflector for the exhaust conduit of an internal combustion engine formed substantially as one half of a hollow cylinder with its forward end open and with the upper surface curving gradually downward and backward, said reflector being positioned with its open side facing downward.

In testimony whereof I hereunto afl ix my signature.

THEODORE P. WRIGHT. 

